Instant messaging (IM) is an Internet Protocol-based application that provides convenient communication between people using a variety of different device types (e.g., computers, mobile phones, etc.). An IM service can be either device-based or network-based.
In a device-based system, the user information is located on the device used to access the system. The user downloads a client application to the device (e.g., a computer, mobile phone). The user's list of contacts and other preferences specific to the user are saved on that device. If the user accesses the system from multiple devices, the same user information will have to be created on each device. If that information is changed, or the user accesses the system as a guest from an infrequently user device, the user information may need to be manually changed on both devices.
In a network-based system, the user information is stored on a network-based server, so users have access to the same customized services and information, regardless of how they access the system. Client software can be loaded on devices used to access the service, but the same contact list, addresses, and other personal information will be available whenever users log into the system. If a change is made to information, that change will then affect all the devices that user uses. Because this information is located centrally, users also have the option of updating their own information for all other users. For example, if a user changes her e-mail address, she can make that change in the system. Then everyone who has the user on their contact list will automatically have their contact lists updated the next time they log into the system. In contrast to the device-based system, the network-based system offers true integrated communications across multiple device types.
In conventional IM-enabled devices, each contact's presence must be manually subscribed and managed, which can be cumbersome. And since there can be several states of presence subscription, the task of managing a large number of presence subscriptions can be overwhelming to most users.
Therefore, what is needed is a system and method for managing presence subscriptions for messaging services, such as IM.